Display panel and method for fabricating the same

ABSTRACT

The display panel of this invention includes a pair of glass substrates each with a thickness not less than 0.15 mm and not more than 0.3 mm and a sealing material for bonding the pair of glass substrates to each other. A resin layer is formed on the outer face of at least one of the pair of glass substrates.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to a display panel and a method forfabricating the display panel. The display panel of this invention isapplicable to a liquid crystal panel, a plasma display panel, anelectrochromic display panel and the like.

[0002] In order to reduce the thickness of a liquid crystal panel, thatis, one of display devices, reduction in the thickness of a substratehas been conventionally examined. In a current liquid crystal panel, apair of glass substrates each having a thickness of 3 mm through 0.4 mmare generally used, and a liquid crystal layer with a thickness ofseveral sum is interposed between these substrates. When a glasssubstrate with a thickness smaller than 0.4 mm is used, the mechanicalstrength is lowered, and hence, there arises, for example, a problemthat the glass substrate is broken during the use.

[0003] Japanese Laid-Open Patent Publication No. 6-340029 discloses alayered plate in which a glass film with a thickness of 500 μm or lessis provided on one face or both faces of a resin plate composed of atleast one resin layer. This layered plate has surface hardnessequivalent to that of glass and a thermal characteristic and a cutcharacteristic of the resin as well as surface characteristics such assolvent resistance and an anti-static property equivalent to those ofglass.

[0004] Japanese Laid-Open Patent Publication No. 2001-113631 discloses aplastic/glass film layered product in which a plastic film with athickness not less than 1 μm and not more than 1000 μm is provided andfixed on at least one face of a glass film with a thickness not lessthan 0.1 μm and not more than 100 μm. This layered product has chemicalresistance, abrasive resistance and a gas barrier property equivalent tothose of glass and is good at a handling property and a fabricationquality.

[0005] Japanese Laid-Open Patent Publication No. 2001-162721 discloses aheat-curing type resin composite in which a covering layer of a glassfilm or a combination of a glass film and a resin layer is fixed on aface of a heat-curing type resin body. Also, it is described inParagraph 0041 of this publication that the glass film has a thicknessof preferably 0.1 through 100 μm and more preferably 0.1 through 20 μm.

[0006] None of the aforementioned publications discloses use of thelayered product or the composite described therein as a substrate for adisplay device. The present inventors have fabricated liquid crystalpanels by using these layered product and the composite and using afabrication line for liquid crystal panels, resulting finding thefollowing:

[0007] First, in order that a liquid crystal panel resists impactapplied on the fabrication line, both faces of a glass substrate shouldbe coated with a resin. Accordingly, the total thickness of the layeredproduct or the composite is increased, and hence, it is difficult toreduce the thickness and the weight of a display device. In addition,the fabrication cost is increased.

[0008] Secondly, since the heat resistance temperature is varied(approximately between 250° C. through 300° C.) depending upon the kindof resin to be employed, the quantity of heat appliable to the layeredproduct or the composite during the fabrication process is restricted.Also, in placing a resin layer on a glass substrate and inheating/cooling process for the layered plate, a warp is caused in thelayered product or the composite due to the difference in thecoefficient of thermal expansion between the glass and the resin, andhence, the ratio of defectives is high. For example, in the case where alayered substrate in which a resin layer is provided on a glasssubstrate with a thickness of approximately 0.2 mm is allowed to passthrough the fabrication line, when the heating/cooling process isrepeated, a warp is caused in the substrate due to the difference in thecoefficient of thermal expansion between the glass and the resin even ata temperature lower than the heat resistance temperature of the resin.As a result, a problem may occur that the substrate is broken or thepatterning accuracy or the aligning accuracy is lowered. Accordingly,due to these restrictions on the fabrication line, the layered productand the composite disclosed in the aforementioned publications cannot besuitably used for mass production of liquid crystal panels.

[0009] On the other hand, Japanese Laid-Open Publication No. 2002-297054discloses a substrate for a display device using a layered sheetincluding a glass layer with a thickness of 50 through 700 μm and resinlayers, each with a thickness of 1 through 7000 μm and a given averagecoefficient of linear thermal expansion, on both faces of the glasslayer. According to the substrate for a display device disclosed in thispublication, since the difference in the average coefficient of linearthermal expansion between the glass layer and the resin layers is small,change such as a crack is not observed in the resin layers in a heatresistance evaluation test. In this substrate for a display device,however, since the resin layers are formed on the faces of the glasslayer, when a pair of these substrates for a display device are used forfabricating a liquid crystal panel, the thickness of the liquid crystalpanel is large. Thus, it is difficult to reduce the thickness and theweight of the display panel.

SUMMARY OF THE INVENTION

[0010] An object of the invention is realizing a small thickness and asmall weight of a display panel freely from restrictions on thefabrication line.

[0011] The display panel according to a first aspect of the inventionincludes a pair of glass substrates each having a thickness not lessthan 0.15 mm and not more than 0.3 mm; and a sealing material forbonding the pair of glass substrates to each other, and a resin layer isformed on an outer face of at least one of the pair of glass substrates.

[0012] In this display panel, the mechanical strength of the displaypanel is improved by covering merely the outer face of the one or twoglass substrates with the resin. This is because sufficient strengthagainst external stress can be secured by reinforcing merely theoutermost face of the display panel with the resin since the opposingtwo glass substrates are bonded to each other with the sealing material.Accordingly, as compared with the case where the both faces of therespective two glass substrates are reinforced, the total thickness ofthe resin layer is smaller in this display panel, and hence, a smallthickness and a small weight of the display panel can be realized. Also,since this display panel has mechanical strength sufficient forresisting impact applied on a fabrication line, the display panel issuitable for mass production using the fabrication line.

[0013] The resin layer may be mainly made of an organic resin. Thus, ascompared with a display panel having an exposed glass substrate, theabrasive resistance can be improved, so that the surface of the displaypanel can be hardly damaged. Also, since the organic resin layer isformed on the glass substrate, the resin layer can be formed even on aglass substrate with a comparatively small curvature. Thus, a flexibleand hard resin-glass layered plate can be obtained.

[0014] The resin layer may include a hybrid material composed ofinorganic colloid particles and an organic binder resin. Since aninorganic-organic composite thin film including the hybrid material hasnot only organic properties but also inorganic properties, the dynamiccharacteristics such as an elastic modulus and hardness are improved,and the heat resistance and the chemical resistance are remarkablyimproved.

[0015] The resin layer preferably has a thickness not less than 2 μm andnot more than 50 μm. Thus, sufficient mechanical strength can beprovided to a thinned glass substrate with a thickness not less than0.15 mm and not more than 0.3 mm, and the fabrication quality can bealso improved, resulting in realizing a small thickness and a smallweight.

[0016] One of the pair of glass substrates may have a terminal portionon its inner face and outside the sealing material, and a resin layermay be formed on the terminal portion. In a display panel, a terminalportion corresponds to one glass substrate disposed outside a sealingmaterial and hence is the weakest against stress due to its structure.When the resin layer is formed on the terminal portion, in other words,when the both faces of the terminal portion alone are coated with theresin, the terminal portion that is the weakest against stress due toits structure can be effectively reinforced.

[0017] An integrated circuit chip is preferably mounted on the terminalportion, and at least a connection part between the terminal and theintegrated circuit chip is preferably covered with a resin. Thus, theconnection part between the terminal and the integrated circuit chip isreinforced by the resin coat, so as to improve the connectionreliability.

[0018] A polarizing layer may be formed on an inner face of at least oneof the pair of glass substrates. Thus, when a light modulation layersuch as a liquid crystal layer is interposed between the pair ofsubstrates, retardation change derived from a tolerance in the glassthickness caused by etching or a tolerance in the thickness of the resinlayer can be suppressed. Also, the strength of the glass substrate canbe improved.

[0019] The display panel according to a second aspect of the inventionincludes a pair of glass substrates each with a thickness not less than0.15 mm and not more than 0.3 mm; and a sealing material for bonding thepair of glass substrates to each other, and at least part of end facesof the pair of glass substrates has a resin layer.

[0020] In the display panel according to the second aspect, at leastpart of the end faces is covered with the resin, so as to improve themechanical strength of the display panel. This is because the strengthcan be improved by coating, with the resin, the edge of the displaypanel, which is the weakest against stress due to its structure.Accordingly, as compared with the case where the both faces of therespective two glass substrates are reinforced, the total thickness ofthe resin layer is smaller in this display panel, and hence, a smallthickness and a small weight of the display panel can be realized. Also,since this display panel has mechanical strength sufficient forresisting impact applied on a fabrication line, the display panel issuitable for mass production using the fabrication line.

[0021] In the display panel of the second aspect, the sealing materialmay have an injection port sealed with the resin layer. Thus, not onlythe strength of the edge of the display panel can be improved but alsothe injection port of the sealing material can be sealed so as toprevent a display medium such as a liquid crystal material from leakingthrough the injection port. Also, when the injection port is sealed withan end-sealing material, the end-sealing material may be shifted orpeeled off due to impact applied on the fabrication line so that thedisplay medium can leak through the injection port. In contrast, whenthe injection port of the sealing material is covered with the resin,the display medium can be prevented from leaking through the injectionport even when the end-sealing material is shifted or the like.

[0022] In the display panel of the second aspect, each of the pair ofglass substrates preferably has an outer face on which a resin layer isformed. Alternatively, a whole face of the display panel is preferablycovered with a resin layer. Thus, high mechanical strength and highreliability can be attained. Also, as compared with the case where theboth faces of the respective two glass substrates are reinforced, thetotal thickness of the display panel can be small, so as to realize asmall thickness and a small weight of the display panel.

[0023] The method according to the first aspect of the invention forfabricating the display panel according to the first aspect, includesthe steps of aligning a pair of glass substrates each with a thicknessof 0.3 mm or more with the sealing material sandwiched therebetween;reducing thicknesses of the pair of aligned glass substrates until eachthickness becomes not less than 0.15 mm and not more than 0.3 mm; andforming the resin layer on the outer face of at least one of the pair ofglass substrates whose thicknesses have been reduced.

[0024] In this fabrication method, the step of aligning substrates iscarried out before the step of forming a resin layer, and therefore,restriction in the quantity of heat appliable in the fabrication processcan be relaxed. Furthermore, in obtaining a layered plate by providingthe resin layer on the glass substrate or in process for applying heatto the layered plate such as pressing process, the layered plate can beprevented from having a warp due to a difference in the coefficient ofthermal expansion between the glass and the resin (for example, aplastic). Moreover, the problem such as lowering of alignment accuracycan be avoided in the step of aligning the substrates. Accordingly, athin resin (for example, a plastic film) tempered glass substrate can beeasily obtained.

[0025] The step of reducing thicknesses preferably includes a sub-stepof performing chemical etching or physical polishing.

[0026] The method according to the second aspect of the invention forfabricating a display panel that includes a pair of glass substrateseach with a thickness not less than 0.15 mm and not more than 0.3 mm anda sealing material for bonding the pair of glass substrates to eachother and in which a resin layer is formed on both faces of the displaypanel, includes the steps of forming a pair of layered plates(glass-resin-glass) each by placing a supporting substrate on each ofthe pair of glass substrates with the resin layer sandwichedtherebetween; aligning the pair of layered plates with the sealingmaterial sandwiched therebetween and with the supporting substratesfacing outside; and removing the supporting substrates from the pair ofaligned layered plates by chemical etching.

[0027] The supporting substrate has a thickness of preferably 0.5 mm ormore, and more preferably 0.7 mm or more. The resin layer preferably hasa thickness not less than 2 μm and not more than 50 μm. The resin layeris preferably a layer mainly made of an organic resin, or a layerincluding a hybrid material composed of inorganic colloid particles andan organic binder resin.

[0028] In this fabrication method, since the layered plate has asufficiently large thickness, the mechanical strength on the fabricationline can be secured. Also, since the supporting substrate can besufficiently thick, a warp of the substrate caused by a difference inthe coefficient of thermal expansion can be suppressed. In other words,this substrate is free from the temperature restriction. Accordingly,the substrates can be stably aligned with the sealing materialsandwiched therebetween. Furthermore, in removing the supportingsubstrates by the chemical etching after the alignment, the resin layercan work as an etching stopper, and therefore, the total thickness ofthe resin layer and the glass substrate can be made uniform.

[0029] The method according to the third aspect of the invention forfabricating a display panel that includes a pair of glass substrateseach with a thickness not less than 0.15 mm and not more than 0.3 mm, asealing material for bonding the pair of glass substrates to each otherand a liquid crystal material filled in a space formed by the pair ofglass substrates and the sealing material, includes the steps ofaligning a pair of glass substrates each with a thickness of 0.3 mm ormore with the sealing material having an injection port sandwichedtherebetween; exposing the injection port of the sealing material on endfaces of the pair of glass substrates by breaking the pair of alignedglass substrates; reducing thicknesses of the pair of glass substratesuntil each thickness becomes not less than 0.15 mm and not more than 0.3mm; filling the liquid crystal material in the space through theinjection port; and forming a resin layer on at least end facescorresponding to the injection port among all end faces of the pair ofglass substrates.

[0030] In this fabrication method, a display panel having mechanicalstrength improved at its edge can be easily fabricated. Also, since themechanical strength of the edge is improved as well as the injectionport of the sealing material can be sealed by covering the end facescorresponding to the injection port with the resin, increase of thenumber of procedures can be suppressed, so as to realize high efficiencyand low cost. In the case where a plurality of liquid crystal panels areobtained from mother glass substrates, the breaking processing forexposing the injection ports and obtaining each cell (terminal exposure)can be carried out in one procedure, and hence, stress applied in thebreaking process can be largely reduced. In this fabrication method,since the thicknesses of the substrates are reduced after the breakingprocessing, the occurrence of defectives can be suppressed as comparedwith the case where thinned glass substrates are subjected to thebreaking processing.

[0031] The method according to the fourth aspect of the invention forfabricating a display panel that includes a pair of glass substrateseach with a thickness not less than 0.15 mm and not more than 0.3 mm, asealing material for bonding the pair of glass substrates each other anda liquid crystal material filled in a space formed by the pair of glasssubstrates and the sealing material, includes the steps of forming thesealing material on one of a pair of glass substrates each with athickness of 0.3 mm or more; dropping the liquid crystal material in aportion surrounded with the sealing material; aligning the pair of glasssubstrates with the sealing material sandwiched therebetween; reducingthicknesses of the pair of aligned glass substrates until each thicknessbecomes not less than 0.15 mm and not more than 0.3 mm; and forming aresin layer on at least part of end faces of the pair of glasssubstrates.

[0032] In this fabrication method, a display panel having mechanicalstrength improved at its edge can be easily fabricated. Also, the liquidcrystal material is filled before reducing the thicknesses of the glasssubstrates. Therefore, the substrates can be prevented from beingcracked by external stress. Accordingly, a thin display panel can beeasily fabricated without lowering the yield.

[0033] The step of reducing thicknesses preferably includes a sub-stepof performing chemical etching or physical polishing.

[0034] The step of forming a resin layer preferably includes a sub-stepof covering end faces and outer faces of the pair of glass substrateswith the resin layer. In this fabrication method, the step of aligningsubstrates is performed before forming the resin layer on the end facesand the outer faces of the pair of glass substrates, in other words, thewhole outer face of the display panel. Therefore, the restriction in thequantity of heat appliable in the fabrication process can be relaxed.Furthermore, in obtaining a layered plate by providing the resin layeron the glass substrate or in process for applying heat to the layeredplate such as pressing process, the layered plate can be prevented fromhaving a warp due to a difference in the coefficient of thermalexpansion between the glass and the resin (for example, a plastic).Moreover, the problem such as lowering of alignment accuracy can beavoided in the step of aligning the substrates. Accordingly, a thinresin (for example, a plastic film) tempered glass substrate can beeasily obtained.

BRIEF DESCRIPTION OF THE DRAWINGS

[0035]FIG. 1 is a plan view for schematically showing a liquid crystalpanel P1 according to Embodiment 1 of the invention;

[0036]FIG. 2 is a cross-sectional view taken along line II-II of FIG. 1;

[0037]FIGS. 3A, 3B and 3C are plan views for schematically showingfabrication procedures for the liquid crystal panel P1;

[0038]FIGS. 4A, 4B and 4C are cross-sectional views for schematicallyshowing fabrication procedures for the liquid crystal panel P1, andspecifically, FIGS. 4A and 4B are cross-sectional views taken along lineIVA-IVA of FIG. 3A and line IVB-IVB of FIG. 3B, respectively;

[0039]FIG. 5 is a cross-sectional view for schematically showing aliquid crystal panel P2 according to Embodiment 2 of the invention;

[0040]FIG. 6 is a plan view for schematically showing a liquid crystalpanel P3 according to Embodiment 3 of the invention;

[0041]FIG. 7 is a cross-sectional view taken along line VII-VII of FIG.6;

[0042]FIGS. 8A and 8B are plan views for schematically showingfabrication procedures for the liquid crystal panel P3;

[0043]FIGS. 9A, 9B and 9C are cross-sectional views for schematicallyshowing fabrication procedures for the liquid crystal panel P3, andspecifically, FIGS. 9A and 9B are cross-sectional views taken along lineIXA-IXA of FIG. 8A and line IXB-IXB of FIG. 8B, respectively;

[0044]FIGS. 10A, 10B and 10C are cross-sectional views for schematicallyshowing fabrication procedures for a liquid crystal panel according toEmbodiment 4;

[0045]FIG. 11 is a plan view for schematically showing a liquid crystalpanel P4 according to Embodiment 6;

[0046]FIG. 12 is a cross-sectional view taken along line XII-XII of FIG.11;

[0047]FIG. 13 is a cross-sectional view taken along line XIII-XIII ofFIG. 11;

[0048]FIGS. 14A, 14B and 14C are plan views for schematically showingfabrication procedures for the liquid crystal panel P4;

[0049]FIGS. 15A, 15B and 15C are cross-sectional views for schematicallyshowing fabrication procedures for the liquid crystal panel P4;

[0050]FIG. 16 is a plan view for schematically showing a liquid crystalpanel P5 according to Embodiment 7;

[0051]FIG. 17 is a cross-sectional view taken along line XVII-XVII ofFIG. 16;

[0052]FIG. 18 is a plan view for schematically showing a liquid crystalpanel according to Embodiment 9;

[0053]FIG. 19 is a cross-sectional view taken along line XIX-XIX of FIG.18;

[0054]FIGS. 20A and 20B are plan views for schematically showingfabrication procedures for a liquid crystal panel P6 according toEmbodiment 10; and

[0055]FIGS. 21A, 21B and 21C are cross-sectional views for schematicallyshowing fabrication procedures for the liquid crystal panel P6, andspecifically, FIGS. 21A and 21B are cross-sectional views taken alongline XXIA-XXIA of FIG. 20A and line XXIB-XXIB of FIG. 20B, respectively.

DETAILED DESCRIPTION OF THE INVENTION

[0056] Preferred embodiments of the invention will now be described withreference to the accompanying drawings. In each of the followingembodiments, a liquid crystal panel is described as an example of adisplay panel, and the display panel according to this invention isapplicable to any of display panels other than the liquid crystal panel.Specifically, the display panel of this invention is applicable to anydisplay device employing, as a display medium, an optical medium otherthan a liquid crystal material, such as a plasma display panel (PDP), aninorganic or organic EL (electroluminescence) display panel, anelectrochromic display (ECD) panel or an electrophoretic display panel.Also, the display panel of this invention can be used as a parallaxbarrier device used in a stereo image display device or as a liquidcrystal device used in an image shift device. It is noted that thestereo image display device includes a parallax barrier device and apicture display device having, for example, a pixel portion for a righteye and a pixel portion for a left eye, and the image shift deviceincludes a liquid crystal device and a birefringence device.

[0057] Embodiment 1

[0058]FIG. 1 is a plan view for schematically showing a liquid crystalpanel P1 according to Embodiment 1, and FIG. 2 is a cross-sectional viewthereof taken along line II-II of FIG. 1. This liquid crystal panel P1includes an IC chip for driving a liquid crystal (hereinafter referredto as the “driving IC”) 10 mounted in the form of a bare chip on theliquid crystal panel P1 by the COG (Chip On Glass) method.

[0059] The liquid crystal panel P1 has an element substrate 1 on which aswitching element is formed, a counter substrate 2 disposed to opposethe element substrate 1, and a liquid crystal layer 3 interposed betweenthese substrates 1 and 2. The substrates 1 and 2 are aligned with asealing material 4 sandwiched therebetween. On one face of the elementsubstrate 1 on the side of the liquid crystal layer 3 (namely, the innerface), a plurality of pixel electrodes (not shown) arranged in the formof a matrix are formed, and on one face of the counter substrate 2 onthe side of the liquid crystal layer 3 (namely, the inner face), acommon electrode (not shown) is formed. The plural pixel electrodesarranged in the form of a matrix are respectively connected to TFTs(Thin Film Transistors) for controlling respective voltage application.The TFTs are connected to source lines and gate lines connected to thedriving IC 10. The switching of each TFT is controlled in accordancewith a gate signal supplied from the driving IC 10, so as to control thevoltage application to the plural pixel electrodes arranged in the formof a matrix. Thus, the transmissivity of the liquid crystal layer 3 ineach pixel is controlled for producing gray scale display.

[0060] Each of the element substrate 1 and the counter substrate 2 is aglass substrate with a thickness not less than 0.15 mm and not more than0.3 mm. One face on the opposite side of the liquid crystal layer 3(namely, the outer face) of at least one of the substrates 1 and 2 iscovered with a resin layer 5. In this embodiment, the resin layer 5 isformed on the outer faces of both the substrates 1 and 2.

[0061] On the inner face of the element substrate 1, a terminal (notshown) is formed outside the sealing material 4. The terminal isconnected to the source line or the gate line formed on the elementsubstrate 1. A bump of the driving IC 10 is bonded to this terminal sothat the driving IC 10 can be mounted in the form of a bare chip on theliquid crystal panel P1. Herein, a portion of the element substrate 1that is outside the sealing material 4 and in which or in the vicinityof which the terminal is formed is designated as a terminal portion 1 a.

[0062] Next, fabrication process for the liquid crystal panel P1 of thisembodiment will be described with reference to the accompanyingdrawings. FIGS. 3A, 3B and 3C are plan views for schematically showingfabrication procedures for the liquid crystal panel P1. FIGS. 4A, 4B and4C are cross-sectional views for schematically showing fabricationprocedures for the liquid crystal panel P1, and more specifically, FIGS.4A and 4B are cross-sectional views taken along line IVA-IVA of FIG. 3Aand line IVB-IVB of FIG. 3B, respectively.

[0063] First, TFT devices, source lines, gate lines, pixel electrodesincluding ITO (Indium Tin Oxide) and the like, and an alignment layerfor covering the pixel electrodes (these elements are not shown) areformed on a soda glass substrate with a thickness of 0.4 mm, and thealignment layer is then subjected to the rubbing processing. Thus, anelement substrate 1 is obtained. Also, a color filter layer and analignment layer (both not shown) are formed on another soda glasssubstrate with a thickness of 0.4 mm, and the alignment layer is thensubjected to the rubbing processing. Thus, a counter substrate 2 isobtained.

[0064] In a peripheral region on the element substrate 1, a sealingmaterial 4 for surrounding a display area is formed. The sealingmaterial 4 can be formed by the dispenser method in which a sealingpattern is drawn on the substrate 1 by using a dispenser or by thescreen printing method in which a sealing pattern already patterned isprinted on the substrate 1. As the sealing material 4, a heat-curingtype resin or a ultraviolet curing type resin is used. After positioningthe substrates 1 and 2, the substrates 1 and 2 are aligned with thesealing material 4 sandwiched therebetween. While pressing thesubstrates 1 and 2 to each other, the substrates 1 and 2 are heated orirradiated with ultraviolet so as to be aligned (as shown in FIGS. 3Aand 4A). It is noted that the sealing material 4 has an injection port 4a through which a liquid crystal material is filled.

[0065] A UV (ultraviolet) curing type adhesive 6 is permeated by using adispenser into a peripheral portion between the substrates 1 and 2. Theadhesive 6 is cured by using a UV irradiation device, so that the insidebetween the substrates can be sealed and isolated from the outside (asshown in FIGS. 3B and 4B).

[0066] The substrates 1 and 2 are reduced in their thicknesses bychemical etching in which the outer faces of the substrates 1 and 2 areexposed to hydrofluoric acid. This thickness reduction is performeduntil the thickness of each of the substrates 1 and 2 becomes not lessthan 0.1 mm and not more than 0.3 mm, namely, until the total thicknessof the aligned substrates becomes approximately not less than 0.2 mm andnot more than 0.6 mm. Although the thicknesses are reduced by thechemical etching in this embodiment, the thicknesses may be reduced byphysical polishing instead. In the case where the physical polishing isemployed, there is no need to seal the edges of the substrates with theUV curing type adhesive 6.

[0067] An acrylic resin is used as a heat-curing type resin material,which is applied on the outer faces of the substrates 1 and 2 by using aspin coater. The resultant is heated at approximately 200° C., so as toform a resin layer 5 with a thickness not less than 1 μM and not morethan 10 μm, and preferably not less than 2 μm and not more than 50 μm.Thus, the liquid crystal panel P1 is obtained (as shown in FIG. 4C).

[0068] Although the heat-curing type resin is used in this embodiment, aUV (ultraviolet) curing type resin may be used for forming the resinlayer 5. Examples of the resin are organic resins such as an epoxyresin, a PES (polyether sulfone) resin, a urethane resin, and a vinylacetate resin. The resin layer 5 is mainly made of an organic resin.Alternatively, a hybrid material highly adhesive to the glass substrateis preferably used instead of the organic resin. When the hybridmaterial is used, the dynamic characteristics such as an elastic modulusand hardness are improved, and the heat resistance and the chemicalresistance are remarkably improved. The hybrid material is composed ofinorganic colloid particles and an organic binder resin. For example,the hybrid material is composed of inorganic colloid particles of silicaor the like and an organic binder resin such as an epoxy resin, apolyurethane acrylate resin or a polyester acrylate resin.

[0069] After forming the resin layer 5, the liquid crystal panel P1 issubjected to the breaking processing for obtaining a predetermined sizeand the adhered portion with the adhesive 6 is removed. Also, theinjection port 4 a of the sealing material 4 is exposed on the end facesof the substrates 1 and 2. In the breaking processing, a scribe line isdrawn on the face of the glass substrate so that the glass substrate canbe broken along the scribe line. After the breaking processing, aportion of the counter substrate opposing the terminal portion 1 a ofthe element substrate 1 is broken to be removed, so as to expose theinner face of the terminal portion 1 a (as shown in FIG. 3C).Hereinafter, this exposure of the inner face of the terminal portion 1 ais sometimes designated as “terminal exposure”.

[0070] The liquid crystal material is filled through the injection port4 a of the sealing material 4 so as to form a liquid crystal layer 3between the substrates 1 and 2. The liquid crystal material can befilled by the dispenser method or the dipping method. After filling theliquid crystal material, the injection port 4 a is sealed with anend-sealing material 7. Specifically, a dispenser is used for applying aheat-curing or UV curing type resin on the injection port 4 a, and theapplied resin is cured by heating or irradiating with UV. Thereafter, adriving IC 10 is mounted in the form of a bare chip on the inner face ofthe terminal portion 1 a of the element substrate 1. Thus, the liquidcrystal panel P1 of this embodiment is completed (see FIG. 1).

TEST EXAMPLE

[0071] A variety of liquid crystal panels each having differentthicknesses of glass substrates and resin layers are fabricated. Theseliquid crystal panels are used for examining occurrence of cracks duringthe breaking processing and the terminal exposure. The results arelisted in Table 1 below. TABLE 1 No resin layer Resin layer of 1 μmResin layer of 2 μm Spoiled Spoiled Spoiled Glass in in in thicknessCrack in terminal Crack in terminal Crack in terminal (mm) No. breakingexposure No. breaking exposure No. breaking exposure 0.10 x x x x 7 x x0.15 x x 4 x x 8 ∘ ∘ 0.20 x x 5 ∘ x ∘ ∘ 0.25 1 x x 6 ∘ ∘ ∘ ∘ 0.30 2 ∘ x∘ ∘ ∘ ∘ 0.35 3 ∘ ∘ ∘ ∘ ∘ ∘ 0.40 ∘ ∘ ∘ ∘ ∘ ∘

[0072] In the liquid crystal panels having no resin layer, in the casewhere the glass substrate has a thickness of 0.25 mm or less, thesubstrate is too thin to attain breaking accuracy in the breakingprocessing, and hence, cracks are caused in the substrate. Also, sincethe mechanical strength of the terminal portion is so low that theterminal portion is spoiled in the terminal exposure (see the panel No.1 of Table 1). In the case where the glass substrate has a thickness of0.30 mm, the glass substrate is sufficiently thick for avoiding cracksin the breaking processing. However, the terminal portion is spoiled inthe terminal exposure (see the panel No. 2 of Table 1). In the casewhere the glass substrate has a thickness of 0.35 mm or more, no cracksare caused in the substrate in the breaking processing. Also, theterminal portion is not spoiled in the terminal exposure (see the panelNo. 3 of Table 1). However, in the case where the glass substrate has athickness of 0.35 mm or more, the total thickness of the liquid crystalpanel is approximately 0.7 mm, and hence, the object to attain a smallthickness of the liquid crystal panel cannot be achieved.

[0073] In the liquid crystal panels each having a resin layer with athickness of 1 μm, in the case where the glass substrate has a thicknessof 0.15 mm or less, the substrate is too thin to attain breakingaccuracy in the breaking processing, and hence, cracks are caused in thesubstrate. Also, the mechanical strength of the terminal portion is solow that the terminal portion is spoiled in the terminal exposure (seethe panel No. 4 of Table 1). In the case where the glass substrate has athickness of 0.20 mm, the glass substrate is sufficiently thick foravoiding cracks in the breaking processing. However, the terminalportion is spoiled in the terminal exposure (see the panel No. 5 ofTable 1). In the case where the glass substrate has a thickness of 0.25mm or more, no cracks are caused in the substrate in the breakingprocessing. Also, the terminal portion is not spoiled in the terminalexposure (see the panel No. 6 of Table 1). Furthermore, the liquidcrystal panels having the resin layer with a thickness of 1 μm exhibitbetter properties in strength tests such as a drop test than the liquidcrystal panels having no resin layer. Accordingly, it is found that theliquid crystal panels having the resin layer with a thickness of 1 μmare more suitable for the mass production using a fabrication line thanthe liquid crystal panels having no resin layer.

[0074] In the liquid crystal panels having a resin layer with athickness of 2 μm, in the case where the glass substrate has a thicknessof 0.10 mm, the substrate is too thin to attain breaking accuracy in thebreaking processing, and hence, cracks are caused in the substrate.Also, the mechanical strength of the terminal portion is so low that theterminal portion is spoiled in the terminal exposure (see the panel No.7 of Table 1). In the case where the glass substrate has a thickness of0.15 mm, no cracks are caused in the substrate in the breakingprocessing. Also, the terminal portion is not spoiled in the terminalexposure (see the panel No. 8 of Table 1). Although not listed in Table1, a liquid crystal panel having a resin layer with a thickness largerthan 50 μm and a glass substrate with a thickness of 0.15 mm, no cracksare caused and the terminal portion is not spoiled. However, when theresin layer is thicker than 50 μm, the total thickness of the liquidcrystal panel is larger by approximately 0.1 mm than a liquid crystalpanel with no resin layer, and hence, the merit of reducing thethickness cannot be attained. Furthermore, since the specific gravity ofthe resin is larger than that of the glass, the merit of reducing theweight cannot be attained. Therefore, in consideration of the totalthickness and the weight of the liquid crystal panel, the thickness ofthe resin layer is preferably 20 μm or less.

[0075] Embodiment 2

[0076]FIG. 5 is a cross-sectional view for schematically showing aliquid crystal panel P2 according to Embodiment 2. In the drawingsreferred to below, the same reference numerals are used to refer toelements with substantially like functions as those of the liquidcrystal panel P1, so as to omit the description.

[0077] The liquid crystal panel P2 of this embodiment is different fromthe liquid crystal panel P1 of Embodiment 1 in a polarizing layer 8formed on the inner faces of the element substrate 1 and the countersubstrate 2. When the polarizing layer 8 is thus formed in the liquidcrystal panel P2, polarized light can be prevented from being disturbedby in-plane variation in the substrate thickness caused by etching orvariation in the thickness of the resin layer, and hence, the displayquality can be prevented from being harmfully affected by disturbedpolarized light. Furthermore, since the polarizing layer 8 is formed onthe element substrate 1 and the counter substrate 2, the strength of theglass substrates can be improved.

[0078] The fabrication process for the liquid crystal panel P2 of thisembodiment is different from that for the liquid crystal panel P1 ofEmbodiment 1 merely in forming the alignment layer after forming thepolarizing layer 8 on the inner faces of the element substrate 1 and thecounter substrate 2. The polarizing layer 8 can be formed by applying aresin including a dichromatic pigment or dye on the substrate and curingthe resin. Examples of the dichromatic pigment or dye are diazo-based,trisazo-based and anthraquinone-based pigments or dyes.

[0079] Embodiment 3

[0080]FIG. 6 is a plan view for schematically showing a liquid crystalpanel P3 according to Embodiment 3, and FIG. 7 is a cross-sectional viewthereof taken along line VII-VII of FIG. 6. In the liquid crystal panelP3 of this embodiment, a resin layer 5 is formed on the outer face of anelement substrate 1 and the inner face of a terminal portion 1 a of theelement substrate 1. In other words, the resin layer 5 is formed on theboth faces of the terminal portion 1 a. Also, a connection part betweena terminal and a driving IC 10 is covered with a resin. Since theconnection part between the terminal and the driving IC 10 is reinforcedby the resin coat in this manner, the connection reliability can beimproved.

[0081] The fabrication process for the liquid crystal panel P3 of thisembodiment will now be described with reference to the accompanyingdrawings. FIGS. 8A and 8B are plan views for schematically showingfabrication procedures for the liquid crystal panel P3, and FIGS. 9A, 9Band 9C are cross-sectional views for schematically showing fabricationprocedures for the liquid crystal panel P3. More specifically, FIGS. 9Aand 9B are cross-sectional views taken along line IXA-IXA of FIG. 8A andline IXB-IXB of FIG. 8B, respectively.

[0082] First, in the same manner as in Embodiment 1, a TFT device andthe like are formed on a soda glass substrate with a thickness of 0.4mm, so as to obtain an element substrate 1. Also, a color filter layerand the like are formed on another soda glass substrate with a thicknessof 0.4 mm, so as to obtain a counter substrate 2.

[0083] A sealing material 4 for surrounding a display area is formed ina peripheral portion on the element substrate 1 by the screen printingor the like. As the sealing material 4, for example, a ultravioletcuring type resin is used. After dropping a liquid crystal material onthe counter substrate 2, the substrates 1 and 2 are aligned with thesealing material 4 sandwiched therebetween. While pressing thesubstrates 1 and 2 to each other, the substrates 1 and 2 are irradiatedwith ultraviolet for curing the sealing material 4, so as to bond thesubstrates 1 and 2 to each other (as shown in FIGS. 8A and 9A). In thisembodiment, a liquid crystal layer 3 is formed at the same time as thealignment of the substrates 1 and 2.

[0084] After subjecting the liquid crystal panel P3 to the breakingprocessing to obtain a predetermined size, the terminal exposure iscarried out. Thus, the inner face of a terminal portion 1 a of theelement substrate 1 is exposed (as shown in FIGS. 8B and 9B).

[0085] The substrates 1 and 2 are reduced in their thicknesses by thephysical polishing. Specifically, the outer faces of the substrates 1and 2 are polished by using, for example, a polishing machine. Thisthickness reduction is performed until the thickness of each of thesubstrates 1 and 2 becomes not less than 0.1 mm and not more than 0.3mm, in other words, until the total thickness of the aligned substratesbecomes approximately not less than 0.2 mm and not more than 0.6 mm (asshown in FIG. 9C). A bump of a driving IC 10 is bonded to the terminalof the element substrate 1 for mounting the driving IC 10 in the form ofa bare chip on the liquid crystal panel P3.

[0086] An acrylic resin is used as a heat-curing type resin material,which is applied on the outer face of the element substrate 1 and theinner face of the terminal portion 1 a of the element substrate 1 by thedipping method. At this point, since the driving IC 10 is mounted in theform of a bare chip on the inner face of the terminal portion 1 a, aconnection part between the terminal and the driving IC 10 is coatedwith the resin. The resultant is heated at approximately 200° C., so asto form a resin layer 5 with a thickness not less than 1 μm and not morethan 100 μm, and preferably not less than 2 μm and not more than 50 μm.Thus, the liquid crystal panel P3 is completed.

[0087] Although the heat-curing type resin is used in this embodiment, aUV (ultraviolet) curing type resin may be used for forming the resinlayer 5. Examples of the resin are organic resins such as an epoxyresin, a PES (polyether sulfone) resin, a urethane resin, and a vinylacetate resin. The resin layer 5 is mainly made of an organic resin.Alternatively, a hybrid material highly adhesive to the glass substrateis preferably used instead of the organic resin. The hybrid material iscomposed of inorganic colloid particles and an organic binder resin. Forexample, the hybrid material is composed of inorganic colloid particlesof silica or the like and an organic binder resin such as an epoxyresin, a polyurethane acrylate resin or a polyester acrylate resin.

[0088] In this embodiment, the breaking processing and the terminalexposure are carried out before polishing the glass substrates. In otherwords, the polishing is performed while the total thickness of thesubstrates is still large. Accordingly, the thickness can be furtherreduced than in Embodiment 1, and the glass substrate can be polished toa thickness of, for example, 0.1 mm. In the case where the glasssubstrate has a thickness of 0.1 mm, however, the terminal portion isspoiled in forming the resin layer afterward. On the other hand, in thecase where the glass substrate has a thickness of 0.15 mm, the terminalportion 1 a is not spoiled in forming the resin layer. Since the resinlayer 5 is formed not only on the outer face of the element substrate 1but also on the inner face of the terminal portion 1 a, the breakingstrength of the terminal portion 1 a is substantially doubled ascompared with the case where the resin layer 5 is formed on the outerface of the element substrate 1 alone (according to a three-pointbending test performed on the terminal portion by using EZ testermanufactured by Shimadzu Corporation). Accordingly, it is found that theliquid crystal panel P3 of this embodiment is suitable for the massproduction using a fabrication line.

[0089] The resin layer 5 is formed on the whole inner face of theterminal portion 1 a in this embodiment. However, the resin layer 5 maybe formed on part of the inner face of the terminal portion 1 a insteadof the whole inner face. For example, the resin layer 5 may be formed ina portion in the vicinity of the terminal in the terminal portion 1 a,namely, in a portion on the inner face other than the area where theterminal is formed.

[0090] Furthermore, although the connection part between the terminaland the driving IC 10 is coated with the resin in this embodiment, notonly the connection part but also the driving IC 10 itself may be coatedwith the resin. Thus, the connection reliability can be furtherimproved.

[0091] Although the driving IC 10 is mounted by the COG method beforeapplying the resin material on the inner face of the terminal portion 1a in this embodiment, the driving IC 10 may be mounted after applyingthe resin material on the inner face of the terminal portion 1 a andbefore curing the resin material. Alternatively, the driving IC 10 maybe mounted by the COG method before aligning the element substrate 1 andthe counter substrate 2.

[0092] Embodiment 4

[0093] A liquid crystal panel according to Embodiment 4 is identical tothe liquid crystal panel P1 shown in FIGS. 1 and 2, and hence, thedescription of the architecture of the liquid crystal panel of thisembodiment is herein omitted. The fabrication process for the liquidcrystal panel of this embodiment will be described with reference to theaccompanying drawings. FIGS. 10A, 10B and 10C are cross-sectional viewsfor schematically showing fabrication procedures for the liquid crystalpanel of this embodiment.

[0094] First, a glass substrate with a thickness of 0.5 mm or more andpreferably 0.7 mm or more is used as a supporting substrate 9, on which,for example, an acrylic resin is applied as a heat-curing type resinmaterial by using a spin coater or the like. Although the heat-curingtype resin is used in this embodiment, a UV (ultraviolet) curing typeresin may be used instead. Examples of the resin are organic resins suchas an epoxy resin, a PES (polyether sulfone) resin, a urethane resin,and a vinyl acetate resin. Alternatively, a hybrid material highlyadhesive to the glass substrate is preferably used instead of theorganic resin. The hybrid material is composed of inorganic colloidparticles and an organic binder resin. For example, the hybrid materialis composed of inorganic colloid particles of silica or the like and anorganic binder resin such as an epoxy resin, a polyurethane acrylateresin or a polyester acrylate resin.

[0095] A thin glass substrate with a thickness not less than 0.15 mm andnot more than 0.3 mm is placed on the supporting substrate 9 with theapplied resin layer 5 sandwiched therebetween, and thermo-compressionbonding is carried out at approximately 200° C. so as to make thethickness of the resin not less than 1 μm and not more than 100 μm andpreferably not less than 2 μm and not more than 50 μm. Two suchglass-resin-glass layered plates are prepared. A TFT device and the likeare formed on the thin glass substrate of one of the layered plates, soas to obtain an element substrate 1. Similarly, a color filter layer andthe like are formed on the thin glass substrate of the other layeredplate, so as to obtain a counter substrate 2. A sealing material 4 forsurrounding a display area is formed in a peripheral portion on theelement substrate 1. These layered plates are bonded to each other withthe sealing material 4 with the supporting substrates 9 facing outside(as shown in FIG. 10A).

[0096] In the same manner as in Embodiment 1, a UV (ultraviolet) curingtype adhesive 6 is permeated into a peripheral portion between thelayered plates by using a dispenser. The adhesive 6 is cured by using aUV irradiation device, so that the inside between the substrates can besealed and isolated from the outside (as shown in FIG. 10B).

[0097] The supporting substrates 9 are removed by the chemical etchingusing hydrofluoric acid (as shown in FIG. 10C). Thereafter, in the samemanner as in Embodiment 1, the breaking processing, the terminalexposure, the filling of a liquid crystal material, the sealing and theCOG mounting are successively carried out, so as to complete the liquidcrystal panel according to this embodiment (see FIG. 1).

[0098] In this embodiment, since the layered plate has a sufficientlylarge thickness, the mechanical strength can be attained on thefabrication line. Also, since the supporting substrates 9 have asufficiently large thickness, they can be stably bonded to each otherwith the sealing material 4 sandwiched therebetween without beingrestricted in the applied temperature. Furthermore, in removing thesupporting substrates 9 by the chemical etching after aligning thelayered plates, the resin layer 5 can work as an etching stopper, andhence, the total thickness of the resin layer and the glass substratescan be made uniform.

[0099] Embodiment 5

[0100] In each of Embodiments 1 through 4, one liquid crystal panel isobtained from a pair of glass substrates. The present invention isapplicable also to the case where a plurality of liquid crystal panelsare obtained from a pair of mother glass substrates. In obtaining aplurality of liquid crystal panels from a pair of mother glasssubstrates, the number of breaking processing performed on the glasssubstrates is large, and therefore, the external stress applied to theglass substrates is large. According to this invention, however,sufficient strength against the external stress can be secured, andhence, the present invention can attain a remarkable effect in theapplication to the case where a plurality of liquid crystal panels areobtained from a pair of mother glass substrates. For example, since theproduct yield on the fabrication line can be increased, cost increaseresulting from occurrence of defectives can be suppressed.

[0101] Embodiment 6

[0102]FIG. 11 is a plan view for schematically showing a liquid crystalpanel P4 according to Embodiment 6. FIG. 12 is a cross-sectional viewthereof taken along line XII-XII of FIG. 11, and FIG. 13 is across-sectional view thereof taken along line XIII-XIII of FIG. 11. Thisliquid crystal panel P4 includes, in a terminal portion 1 a, a drivingIC 10 mounted in the form of a bare chip on the liquid crystal panel P4by the COG (Chip On Glass) method in the same manner as the liquidcrystal panel P1 of Embodiment 1.

[0103] In the same manner as the liquid crystal panel P1 of Embodiment1, the liquid crystal panel P4 has an element substrate 1 on which aswitching element is formed, a counter substrate 2 disposed to opposethe element substrate 1 and a liquid crystal layer 3 interposed betweenthe substrates 1 and 2. The substrates 1 and 2 are aligned with asealing material 4 sandwiched therebetween.

[0104] The sealing material 4 has an injection port through which aliquid crystal material is filled, and the injection port is sealed withan end-sealing material 7. As shown in FIG. 13, a resin layer 5 isformed on end faces 100 and 200 of the substrates 1 and 2 in thevicinity of the end-sealing material 7. Although the distance (cell gap)between the substrates 1 and 2 is larger than the thickness of thesubstrates 1 and 2 in FIG. 13, the cell gap is typically approximatelyseveral sum while the thickness of the substrates 1 and 2 is not lessthan 0.15 mm and not more than 0.3 mm. Accordingly, the end faces 100and 200 of the substrates 1 and 2 in the vicinity of the end-sealingmaterial 7 can be substantially expressed as the end face of the liquidcrystal panel P4.

[0105] The resin layer 5 may be formed on the whole end faces 100 and200 or may be formed on part of the end faces 100 and 200. In thisembodiment, the resin layer 5 is formed at least in portions of the endfaces corresponding to the injection port. Thus, even when theend-sealing material 7 is shifted or peeled off due to impact applied onthe fabrication line, the liquid crystal material can be prevented fromleaking through the injection port.

[0106] Next, the fabrication process for the liquid crystal panel P4 ofthis embodiment will be described with reference to the accompanyingdrawings. FIGS. 14A, 14B and 14C are plan views for schematicallyshowing fabrication procedures for the liquid crystal panel P4. FIGS.15A, 15B and 15C are cross-sectional views for schematically showingfabrication procedures for the liquid crystal panel P4. Morespecifically, FIGS. 15A and 15B are cross-sectional views taken alongline XVA-XVA of FIG. 14A and line XVB-XVB of FIG. 14B, respectively.

[0107] First, in the same manner as in Embodiment 1, an elementsubstrate 1 and a counter substrate 2 are obtained and these substrates1 and 2 are aligned (as shown in FIGS. 14A and 15A). A UV (ultraviolet)curing type adhesive 6 is permeated into a peripheral portion betweenthe substrates 1 and 2. The adhesive 6 is cured by using a UVirradiation device, so that the inside between the substrates can besealed and isolated from the outside (as shown in FIGS. 14B and 15B).The substrates 1 and 2 are reduced in their thicknesses by the chemicaletching in which the outer faces of the substrates 1 and 2 are exposedto hydrofluoric acid (as shown in FIG. 15C). The thickness reduction isperformed until the thickness of each of the substrates 1 and 2 becomesnot less than 0.1 mm and not more than 0.3 mm, in other words, until thetotal thickness of the aligned substrates becomes approximately not lessthan 0.2 mm and not more than 0.6 mm.

[0108] The aligned substrates 1 and 2 thus reduced in their thicknessesare subjected to the breaking processing so as to obtain a predeterminedsize, and a bonding portion with the adhesive 6 is removed. Also, aninjection port 4 a of the sealing material 4 is exposed on the end facesof the substrates 1 and 2. After the breaking processing, the terminalexposure is performed by removing a portion of the counter substrateopposing the terminal portion 1 a of the element substrate 1 by breaking(as shown in FIG. 14C).

[0109] By utilizing capillarity under reduced pressure, a liquid crystalmaterial is filled through the injection port 4 a of the sealingmaterial 4. Thus, a liquid crystal layer 3 is formed between thesubstrates 1 and 2. The liquid crystal material can be filled by thedispenser method or the dipping method. After filling the liquid crystalmaterial, the injection port 4 a is sealed with an end-sealing material7. Specifically, a heat-curing type or UV curing type resin is appliedon the injection port 4 a by using a dispenser, and the resin is heatedor irradiated with ultraviolet for curing. In this embodiment, theinjection port 4 a is sealed by applying a UV curing type sealer (forexample, S-170 manufactured by Loctite) and curing it through UVirradiation.

[0110] Next, among the end faces of the substrates 1 and 2, end faces100 and 200 in the vicinity of the end-sealing material 7 are coatedwith a resin by the dipping method. The resin is subjected to UVirradiation performed at 350 mJ, so as to form a resin layer 5 with athickness not less than 1 μm and not more than 100 μm and preferably notless than 2 μm and not more than 50 μm. Thereafter, a driving IC 10 ismounted in the form of a bare chip on the inner face of the terminalportion 1 a of the element substrate 1. Thus, the liquid crystal panelP4 of this embodiment is completed (see FIG. 11).

[0111] Although the UV (ultraviolet) curing type resin is used in thisembodiment, a heat-curing type resin may be used for forming the resinlayer 5. Examples of the resin are organic resins such as an epoxyresin, a PES (polyether sulfone) resin, a urethane resin, and a vinylacetate resin. The resin layer 5 is mainly made of an organic resin.Alternatively, a hybrid material highly adhesive to the glass substrateis preferably used instead of the organic resin. When the hybridmaterial is used, the dynamic characteristics such as an elastic modulusand hardness are improved, and the heat resistance and the chemicalresistance are remarkably improved. The hybrid material is composed ofinorganic colloid particles and an organic binder resin. For example,the hybrid material is composed of inorganic colloid particles of silicaor the like and an organic binder resin such as an epoxy resin, apolyurethane acrylate resin or a polyester acrylate resin.

[0112] According to this embodiment, in the fabrication process for theliquid crystal panel P4, the stress applied to the end faces of thepanel can be reduced in, for example, the following procedures, andhence, the substrates can be prevented from cracking and the yield canbe improved:

[0113] 1) Cleaning procedure: For example, when the liquid crystal panelplaced within a cassette is brought into contact with the cassette owingto vibration caused for the cleaning, or when the liquid crystal panelis taken out of the cassette.

[0114] 2) Inspection procedure: For example, when the liquid crystalpanel is set on test equipment.

[0115] 3) Polarizer sticking procedure: When the liquid crystal panel isset on a polarizer sticking system.

[0116] 4) Mounting procedure: When the liquid crystal panel is set on amounting device or when a pressing tool comes into contact with theliquid crystal panel (the terminal portion, in particular).

[0117] 5) Assembling procedure: When the liquid crystal panel isassembled in a unit.

[0118] Embodiment 7

[0119]FIG. 16 is a plan view for schematically showing a liquid crystalpanel P5 according to Embodiment 7. FIG. 17 is a cross-sectional viewthereof taken along line XVII-XVII of FIG. 16.

[0120] The liquid crystal panel P5 of this embodiment is different fromthe liquid crystal panel P4 of Embodiment 6 in the injection port 4 a ofthe sealing material 4 sealed not with the end-sealing material but witha resin layer 5. In this embodiment, the injection port 4 a can besealed by forming the resin layer 5, and therefore, the procedure forforming the end-sealing material can be omitted, resulting insuppressing increase of the number of procedures. Accordingly, theefficiency can be increased and the cost can be lowered. The liquidcrystal panel P5 of this embodiment can be fabricated in the same manneras described in Embodiment 6 except that the procedure for forming theend-sealing material is omitted, and hence, the description of thefabrication method will be herein omitted.

[0121] Embodiment 8

[0122] Although the resin layer 5 is formed merely on the end faces 100and 200 in the vicinity of the end-sealing material 7 in the liquidcrystal panel P4 or P5 of Embodiment 6 or 7, the resin layer 5 may beformed on the other end faces. Also, the resin layer 5 may be formed onthe outer face (namely, the face on the opposite side to the liquidcrystal layer 3) of the element substrate 1 and/or the counter substrate2. The resin layer is formed by, for example, applying the resin on theouter faces of the substrates 1 and 2 by a spin coater, the dippingmethod or the dispenser method and curing the applied resin.

[0123] In a liquid crystal panel of this embodiment, a resin layer witha thickness of 30 μm is formed on three end faces, namely, the end facein the vicinity of the end-sealing material and the end faces adjacentto this end face. Thus, even when stress is applied to the three endfaces of the liquid crystal panel, the edges of the liquid crystal panelcan be prevented from being damaged.

[0124] Furthermore, a resin layer with a thickness of 30 μm is formedalso on the outer faces of the element substrate and the countersubstrate of the liquid crystal panel of this embodiment. Since theresin layer is formed on the outermost faces of the display panel, thepanel can attain more sufficient strength against external stress. Also,as compared with the case where the both faces of the respective twoglass substrates are reinforced, the total thickness of the resin layercan be reduced, so as to realize a small thickness and a small weight ofthe display panel. Furthermore, since this display panel can attainmechanical strength sufficient for resisting compact applied on thefabrication line, it is suitable to the mass production using thefabrication line.

[0125] Embodiment 9

[0126]FIG. 18 is a plan view for schematically showing a liquid crystalpanel P6 according to Embodiment 9, and FIG. 19 is a cross-sectionalview thereof taken along line XIX-XIX of FIG. 18. As shown in FIG. 19,the liquid crystal panel P6 of this embodiment is covered with a resinon its whole faces. Thus, high mechanical strength and high reliabilitycan be attained. Also, as compared with the case where the both faces ofthe respective two glass substrates are reinforced, the total thicknessof the display panel can be reduced, so as to realize a small thicknessand a small weight of the display panel.

[0127] The fabrication process for the liquid crystal panel P6 of thisembodiment will now be described with reference to the accompanyingdrawings. FIGS. 20A and 20B are plan views for schematically showingfabrication procedures for the liquid crystal panel P6, and FIGS. 21A,21B and 21C are cross-sectional views for schematically showingfabrication procedures for the liquid crystal panel P6. Morespecifically, FIGS. 21A and 21B are cross-sectional views taken alongline XXIA-XXIA of FIG. 20A and line XXIB-XXIB of FIG. 20B, respectively.

[0128] First, in the same manner as in Embodiment 6, a TFT device andthe like are formed on a soda glass substrate with a thickness of 0.4mm, so as to obtain an element substrate 1. Also, a color filter layerand the like are formed on another soda glass substrate with a thicknessof 0.4 mm, so as to obtain a counter substrate 2.

[0129] In the same manner as in Embodiment 3, a sealing material 4 forsurrounding a display area is formed in a peripheral portion on theelement substrate 1 by the screen printing or the like. After dropping aliquid crystal material on the counter substrate 2, the substrates 1 and2 are aligned with the sealing material 4 sandwiched therebetween. Whilepressing the substrates 1 and 2 to each other, the substrates 1 and 2are irradiated with ultraviolet so as to cure the sealing material 4.Thus, the substrates 1 and 2 are bonded to each other (as shown in FIGS.20A and 21A). In this embodiment, a liquid crystal layer 3 is formed atthe same time as the alignment of the substrates 1 and 2.

[0130] After subjecting the liquid crystal panel P6 to the breakingprocessing to obtain a predetermined size, the terminal exposure iscarried out. Thus, the inner face of a terminal portion 1 a of theelement substrate 1 is exposed (as shown in FIGS. 20B and 21B).

[0131] The substrates 1 and 2 are reduced in their thicknesses by thephysical polishing. Specifically, the outer faces of the substrates 1and 2 are polished by using, for example, a polishing machine. Thisthickness reduction is performed until the thickness of each of thesubstrates 1 and 2 becomes not more than 0.1 mm and not less than 0.3mm, in other words, until the total thickness of the aligned substratesbecomes approximately not less than 0.2 mm and not more than 0.6 mm (asshown in FIG. 21C). A bump of a driving IC 10 is bonded to the terminalof the element substrate 1 so that the driving IC 10 can be mounted inthe form of a bare chip on the liquid crystal panel P6.

[0132] Next, for example, an acrylic resin is applied on the whole outerface of the liquid crystal panel P6 by the dipping method. The resultantis heated at approximately 200° C., so as to form a resin layer 5 with athickness of 20 μm.

[0133] Although the heat-curing type resin is used in this embodiment, aUV (ultraviolet) curing type resin may be used for forming the resinlayer 5. Examples of the resin are organic resins such as an epoxyresin, a PES (polyether sulfone) resin, a urethane resin, and a vinylacetate resin. The resin layer 5 is mainly made of an organic resin.Alternatively, a hybrid material highly adhesive to the glass substrateis preferably used instead of the organic resin. When the hybridmaterial is used, the dynamic characteristics such as an elastic modulusand hardness are improved, and the heat resistance and the chemicalresistance are remarkably improved. The hybrid material is composed ofinorganic colloid particles and an organic binder resin. For example,the hybrid material is composed of inorganic colloid particles of silicaor the like and an organic binder resin such as an epoxy resin, apolyurethane acrylate resin or a polyester acrylate resin.

[0134] In the case where the thicknesses of the substrates 1 and 2 arereduced by the chemical etching as in Embodiment 4, a UV (ultraviolet)curing type adhesive is permeated into a peripheral portion between thesubstrates 1 and 2 by using a dispenser. The adhesive is cured by usinga UV irradiation device, so that the inside between the substrates canbe sealed and isolated from the outside.

[0135] In this embodiment, the breaking processing and the terminalexposure are carried out before polishing the glass substrates 1 and 2.In other words, the polishing is performed while the total thickness ofthe substrates 1 and 2 is still large. Accordingly, cracks can beprevented from being caused in the substrates 1 and 2 in the breakingprocessing, and the terminal portion 1 a can be prevented from beingspoiled in the terminal exposure. Also, since the thickness reduction isperformed after the breaking processing, the occurrence of defectivescan be suppressed as compared with the case where glass substrateshaving reduced thicknesses are subjected to the breaking processing.

[0136] In this embodiment, the filling and sealing procedures areperformed before reducing the thicknesses of the glass substrates 1 and2, and hence, the substrates can be prevented from being cracked due toexternal stress. As a result, a thin film tempered glass substrate canbe easily fabricated without lowering the yield.

[0137] In obtaining a plurality of liquid crystal panels from a pair ofmother glass substrates, the number of breaking processing performed onthe glass substrates is large, and therefore, the external stressapplied to the glass substrates is large. According to this embodiment,however, in the case where a large number of liquid crystal panels areobtained from mother glass substrates, the breaking processing forexposing the injection ports and obtaining each cell (namely, theterminal exposure) can be carried out in one step, and therefore, thestress applied during the breaking processing can be largely reduced.

[0138] According to this embodiment, in the fabrication process for theliquid crystal panel P6, the stress applied to the end face of the panelcan be reduced in, for example, the following procedures, and hence, thesubstrates can be prevented from cracking and the yield can be improved:

[0139] 1) Cleaning procedure: For example, when the liquid crystal panelplaced within a cassette is brought into contact with the cassette owingto vibration caused for the cleaning, or when the liquid crystal panelis taken out of the cassette.

[0140] 2) Inspection procedure: For example, when the liquid crystalpanel is set on test equipment.

[0141] 3) Polarizer sticking procedure: When the liquid crystal panel isset on a polarizer sticking system.

[0142] 4) Assembling procedure: When the liquid crystal panel isassembled in a unit.

[0143] Although the driving IC 10 is mounted by the COG method beforeapplying the resin material on the inner face of the terminal portion 1a in this embodiment, the driving IC 10 may be mounted after applyingthe resin material on the inner face of the terminal portion 1 a andbefore curing the resin material. Alternatively, the driving IC 10 maybe mounted by the COG method before aligning the element substrate 1 andthe counter substrate 2.

[0144] (Test Example: Drop test)

[0145] Assuming that a display panel is dropped from the top of a deskto the floor, various display panels are dropped from a height of 70 cmto the top of a desk and damages of the edges of the display panels arechecked. As the display panels to be examined, three cells each of theliquid crystal panels of Embodiments 6 through 9 are used. The size ofeach liquid crystal panel is 40 mm×50 mm. Each liquid crystal panel isdropped with its glass substrate face being vertical to the top of thedesk and with the terminal portion 1 a facing upward. With respect tothe liquid crystal panels according to Embodiments 6 through 8, eachliquid crystal panel is dropped with its end face in the vicinity of theinjection port 4 a of the sealing material 4 facing downward.

[0146] As a comparative example, a display panel in which a resin layeris formed merely on the outer faces of the glass substrates is tested bya similar drop test.

[0147] As a result, none of the liquid crystal panels according toEmbodiments 6 through 9 is damaged in their edges (the edges opposite tothe terminal portions 1 a). In contrast, the edge of the liquid crystalpanel of the comparative example is damaged.

[0148] According to this invention, a small thickness and a small weightof a display panel can be realized freely from restrictions on thefabrication line.

What is claimed is:
 1. A display panel comprising: a pair of glasssubstrates each having a thickness not less than 0.15 mm and not morethan 0.3 mm; and a sealing material for bonding the pair of glasssubstrates to each other, wherein a resin layer is formed on an outerface of at least one of the pair of glass substrates.
 2. The displaypanel of claim 1, wherein the resin layer is mainly made of an organicresin.
 3. The display panel of claim 1, wherein the resin layer includesa hybrid material composed of inorganic colloid particles and an organicbinder resin.
 4. The display panel of claim 1, wherein the resin layerhas a thickness not less than 2 μm and not more than 50 μm.
 5. Thedisplay panel of claim 1, wherein one of the pair of glass substrateshas a terminal portion on its inner face and outside the sealingmaterial, and a resin layer is formed on the terminal portion.
 6. Thedisplay panel of claim 5, wherein an integrated circuit chip is mountedon the terminal portion, and at least a connection part between theterminal and the integrated circuit chip is covered with a resin.
 7. Thedisplay panel of claim 1, wherein a polarizing layer is formed on aninner face of at least one of the pair of glass substrates.
 8. A methodfor fabricating the display panel of claim 1, comprising the steps of:aligning a pair of glass substrates each with a thickness of 0.3 mm ormore with the sealing material sandwiched therebetween; reducingthicknesses of the pair of aligned glass substrates until each thicknessbecomes not less than 0.15 mm and not more than 0.3 mm; and forming theresin layer on the outer face of at least one of the pair of glasssubstrates whose thicknesses have been reduced.
 9. The method forfabricating the display panel of claim 8, wherein the step of reducingthicknesses includes a sub-step of performing chemical etching orphysical polishing.
 10. A method for fabricating a display panel thatincludes a pair of glass substrates each with a thickness not less than0.15 mm and not more than 0.3 mm and a sealing material for bonding thepair of glass substrates to each other and in which a resin layer isformed on both faces of the display panel, comprising the steps of:forming a pair of layered plates each by placing a supporting substrateon each of the pair of glass substrates with the resin layer sandwichedtherebetween; aligning the pair of layered plates with the sealingmaterial sandwiched therebetween and with the supporting substratesfacing outside; and removing the supporting substrates from the pair ofaligned layered plates by chemical etching.
 11. The method forfabricating a display panel of claim 10, wherein the supportingsubstrate has a thickness of 0.5 mm or more.
 12. The method forfabricating a display panel of claim 10, wherein the resin layer has athickness not less than 2 μm and not more than 50 μm.
 13. The method forfabricating a display panel of claim 10, wherein the resin layer is alayer mainly made of an organic resin, or a layer including a hybridmaterial composed of inorganic colloid particles and an organic binderresin.
 14. A display panel comprising: a pair of glass substrates eachwith a thickness not less than 0.15 mm and not more than 0.3 mm; and asealing material for bonding the pair of glass substrates to each other,wherein at least part of end faces of the pair of glass substrates has aresin layer.
 15. The display panel of claim 14, wherein the sealingmaterial has an injection port sealed with the resin layer.
 16. Thedisplay panel of claim 14, wherein each of the pair of glass substrateshas an outer face on which a resin layer is formed.
 17. The displaypanel of claim 14, wherein a whole face of the display panel is coveredwith a resin layer.
 18. A method for fabricating a display panel thatincludes a pair of glass substrates each with a thickness not less than0.15 mm and not more than 0.3 mm, a sealing material for bonding thepair of glass substrates to each other and a liquid crystal materialfilled in a space formed by the pair of glass substrates and the sealingmaterial, comprising the steps of: aligning a pair of glass substrateseach with a thickness of 0.3 mm or more with the sealing material havingan injection port sandwiched therebetween; exposing the injection portof the sealing material on end faces of the pair of glass substrates bybreaking the pair of aligned glass substrates; reducing thicknesses ofthe pair of glass substrates until each thickness becomes not less than0.15 mm and not more than 0.3 mm; filling the liquid crystal material inthe space through the injection port; and forming a resin layer on atleast end faces corresponding to the injection port among all end facesof the pair of glass substrates.
 19. A method for fabricating a displaypanel that includes a pair of glass substrates each with a thickness notless than 0.15 mm and not more than 0.3 mm, a sealing material forbonding the pair of glass substrates each other and a liquid crystalmaterial filled in a space formed by the pair of glass substrates andthe sealing material, comprising the steps of: forming the sealingmaterial on one of a pair of glass substrates each with a thickness of0.3 mm or more; dropping the liquid crystal material in a portionsurrounded with the sealing material; aligning the pair of glasssubstrates with the sealing material sandwiched therebetween; reducingthicknesses of the pair of aligned glass substrates until each thicknessbecomes not less than 0.15 mm and not more than 0.3 mm; and forming aresin layer on at least part of end faces of the pair of glasssubstrates.
 20. The method for fabricating a display panel of claim 18,wherein the step of reducing thicknesses includes a sub-step ofperforming chemical etching or physical polishing.
 21. The method forfabricating a display panel of claim 19, wherein the step of reducingthicknesses includes a sub-step of performing chemical etching orphysical polishing.
 22. The method for fabricating a display panel ofclaim 18, wherein the step of forming a resin layer includes a sub-stepof covering end faces and outer faces of the pair of glass substrateswith the resin layer.
 23. The method for fabricating a display panel ofclaim 19, wherein the step of forming a resin layer includes a sub-stepof covering end faces and outer faces of the pair of glass substrateswith the resin layer.